1997 S420 - Secondary air. how dead am I?
 

OK.

I get a P0410 code. The pump is working, starts on cold start - blows hard, turns off etc - seems to be mechanically/electrically working right.

I can't quite tell if the vacuum valve which opens to allow the air into the exhaust system is working right. Mostly because i have no idea how to take it off, anyone? The screws/bolts are on the underside and I have no way of reaching them without taking the front of the car/engine apart - so - any suggestions would be great on how to check that valve.

Does anyone know if the air is fed directly into the exhaust - or does it go through the cylinder head? I'm hoping it's a straight dump to exhaust, because then it's much easier to repair - otherwise I have to take the head off - which just might not be worth it on this car.

Thoughts? HELP!

Adam

Need to check o2 sensor for correct operation needs to see air injected